No experience but it will cost you just a fiver to find out if it works and that may be less than you are paying for bait. Personally I would try it for two months and then if you are still seeing mice around send it back under the warranty.

Mice can collapse their skeletons to squeeze through very small holes, if you can push a ballpoint pen through a mouse can get through.

My mother had a problem a couple of years ago when they spread from next door, council laid poison (no charge). I filled lots of holes to stop them getting in the house including small wire mesh over the air bricks (paranoia from my wife and mother).

None of the other neighbours would admit to having a problem but the council man said he would guarantee the mice would have spread to all houses at least 5 doors away. so kept the traps and poison down for a month after all signs disappeared.

All signs of infestation were gone within a couple of weeks only one found in her house about twenty next door.

When our house was new we had several invasions of field mice especially as winter was drawing near. Personally I think traps are the best method and disposal is not that bad and better than letting them rot away out of site. Mice seldom live alone so be prepared to catch several before they disappear.

We had mice a few years ago and bought a couple of similar plugin units (I think we got 2 for the price of 1) to the one suggested,though ours are somewhat smaller. It may be coincidence but we have not had any mice in the house since. I have just Googled Mice Repellers and this came up:- http://www.maplin.co.uk/sonic-mouse-and-rat-repeller-3-pack-222555?c=maplin&utmsource=gcs&utmmedium=gcssearch&utmcampaign=N86FU&utm_content=Pest+Repellers+%26+Killers These are what we have.